Commit 6ddc5fb4 authored by Roland Stigge's avatar Roland Stigge Committed by Greg Kroah-Hartman

Staging: iio: add driver for MAX517/518/519

IIO Driver for Maxim MAX517, MAX518 and MAX519 DAC
Signed-off-by: default avatarRoland Stigge <stigge@antcom.de>
Acked-by: default avatarJonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 18545cfd
Kernel driver max517
====================
Supported chips:
* Maxim MAX517, MAX518, MAX519
Prefix: 'max517'
Datasheet: Publicly available at the Maxim website
http://www.maxim-ic.com/
Author:
Roland Stigge <stigge@antcom.de>
Description
-----------
The Maxim MAX517/518/519 is an 8-bit DAC on the I2C bus. The following table
shows the different feature sets of the variants MAX517, MAX518 and MAX519:
Feature MAX517 MAX518 MAX519
--------------------------------------------------------------------------
One output channel X
Two output channels X X
Simultaneous output updates X X
Supply voltage as reference X
Separate reference input X
Reference input for each DAC X
Via the iio sysfs interface, there are three attributes available: out1_raw,
out2_raw and out12_raw. With out1_raw and out2_raw, the current output values
(0..255) of the DACs can be written to the device. out12_raw can be used to set
both output channel values simultaneously.
With MAX517, only out1_raw is available.
Via out1_scale (and where appropriate, out2_scale), the current scaling factor
in mV can be read.
When the operating system goes to a power down state, the Power Down function
of the chip is activated, reducing the supply current to 4uA.
On power-up, the device is in 0V-output state.
......@@ -19,3 +19,13 @@ config AD5446
To compile this driver as a module, choose M here: the
module will be called ad5446.
config MAX517
tristate "Maxim MAX517/518/519 DAC driver"
depends on I2C && EXPERIMENTAL
help
If you say yes here you get support for the Maxim chips MAX517,
MAX518 and MAX519 (I2C 8-Bit DACs with rail-to-rail outputs).
This driver can also be built as a module. If so, the module
will be called max517.
......@@ -4,3 +4,4 @@
obj-$(CONFIG_AD5624R_SPI) += ad5624r_spi.o
obj-$(CONFIG_AD5446) += ad5446.o
obj-$(CONFIG_MAX517) += max517.o
/*
* max517.c - Support for Maxim MAX517, MAX518 and MAX519
*
* Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include "../iio.h"
#include "dac.h"
#include "max517.h"
#define MAX517_DRV_NAME "max517"
/* Commands */
#define COMMAND_CHANNEL0 0x00
#define COMMAND_CHANNEL1 0x01 /* for MAX518 and MAX519 */
#define COMMAND_PD 0x08 /* Power Down */
enum max517_device_ids {
ID_MAX517,
ID_MAX518,
ID_MAX519,
};
struct max517_data {
struct iio_dev *indio_dev;
unsigned short vref_mv[2];
};
/*
* channel: bit 0: channel 1
* bit 1: channel 2
* (this way, it's possible to set both channels at once)
*/
static ssize_t max517_set_value(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count, int channel)
{
struct i2c_client *client = to_i2c_client(dev);
u8 outbuf[4]; /* 1x or 2x command + value */
int outbuf_size = 0;
int res;
long val;
res = strict_strtol(buf, 10, &val);
if (res)
return res;
if (val < 0 || val > 255)
return -EINVAL;
if (channel & 1) {
outbuf[outbuf_size++] = COMMAND_CHANNEL0;
outbuf[outbuf_size++] = val;
}
if (channel & 2) {
outbuf[outbuf_size++] = COMMAND_CHANNEL1;
outbuf[outbuf_size++] = val;
}
/*
* At this point, there are always 1 or 2 two-byte commands in
* outbuf. With 2 commands, the device can set two outputs
* simultaneously, latching the values upon the end of the I2C
* transfer.
*/
res = i2c_master_send(client, outbuf, outbuf_size);
if (res < 0)
return res;
return count;
}
static ssize_t max517_set_value_1(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
return max517_set_value(dev, attr, buf, count, 1);
}
static IIO_DEV_ATTR_OUT_RAW(1, max517_set_value_1, 0);
static ssize_t max517_set_value_2(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
return max517_set_value(dev, attr, buf, count, 2);
}
static IIO_DEV_ATTR_OUT_RAW(2, max517_set_value_2, 1);
static ssize_t max517_set_value_both(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
return max517_set_value(dev, attr, buf, count, 3);
}
static IIO_DEVICE_ATTR_NAMED(out1and2_raw, out1&2_raw, S_IWUSR, NULL,
max517_set_value_both, -1);
static ssize_t max517_show_scale(struct device *dev,
struct device_attribute *attr,
char *buf, int channel)
{
struct iio_dev *dev_info = dev_get_drvdata(dev);
struct max517_data *data = iio_dev_get_devdata(dev_info);
/* Corresponds to Vref / 2^(bits) */
unsigned int scale_uv = (data->vref_mv[channel - 1] * 1000) >> 8;
return sprintf(buf, "%d.%03d\n", scale_uv / 1000, scale_uv % 1000);
}
static ssize_t max517_show_scale1(struct device *dev,
struct device_attribute *attr,
char *buf)
{
return max517_show_scale(dev, attr, buf, 1);
}
static IIO_DEVICE_ATTR(out1_scale, S_IRUGO, max517_show_scale1, NULL, 0);
static ssize_t max517_show_scale2(struct device *dev,
struct device_attribute *attr,
char *buf)
{
return max517_show_scale(dev, attr, buf, 2);
}
static IIO_DEVICE_ATTR(out2_scale, S_IRUGO, max517_show_scale2, NULL, 0);
/* On MAX517 variant, we have two outputs */
static struct attribute *max517_attributes[] = {
&iio_dev_attr_out1_raw.dev_attr.attr,
&iio_dev_attr_out1_scale.dev_attr.attr,
NULL
};
static struct attribute_group max517_attribute_group = {
.attrs = max517_attributes,
};
/* On MAX518 and MAX518 variant, we have two outputs */
static struct attribute *max518_attributes[] = {
&iio_dev_attr_out1_raw.dev_attr.attr,
&iio_dev_attr_out1_scale.dev_attr.attr,
&iio_dev_attr_out2_raw.dev_attr.attr,
&iio_dev_attr_out2_scale.dev_attr.attr,
&iio_dev_attr_out1and2_raw.dev_attr.attr,
NULL
};
static struct attribute_group max518_attribute_group = {
.attrs = max518_attributes,
};
static int max517_suspend(struct i2c_client *client, pm_message_t mesg)
{
u8 outbuf = COMMAND_PD;
return i2c_master_send(client, &outbuf, 1);
}
static int max517_resume(struct i2c_client *client)
{
u8 outbuf = 0;
return i2c_master_send(client, &outbuf, 1);
}
static int max517_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct max517_data *data;
struct max517_platform_data *platform_data = client->dev.platform_data;
int err;
data = kzalloc(sizeof(struct max517_data), GFP_KERNEL);
if (!data) {
err = -ENOMEM;
goto exit;
}
i2c_set_clientdata(client, data);
data->indio_dev = iio_allocate_device();
if (data->indio_dev == NULL) {
err = -ENOMEM;
goto exit_free_data;
}
/* establish that the iio_dev is a child of the i2c device */
data->indio_dev->dev.parent = &client->dev;
/* reduced attribute set for MAX517 */
if (id->driver_data == ID_MAX517)
data->indio_dev->attrs = &max517_attribute_group;
else
data->indio_dev->attrs = &max518_attribute_group;
data->indio_dev->dev_data = (void *)(data);
data->indio_dev->driver_module = THIS_MODULE;
data->indio_dev->modes = INDIO_DIRECT_MODE;
/*
* Reference voltage on MAX518 and default is 5V, else take vref_mv
* from platform_data
*/
if (id->driver_data == ID_MAX518 || !platform_data) {
data->vref_mv[0] = data->vref_mv[1] = 5000; /* mV */
} else {
data->vref_mv[0] = platform_data->vref_mv[0];
data->vref_mv[1] = platform_data->vref_mv[1];
}
err = iio_device_register(data->indio_dev);
if (err)
goto exit_free_device;
dev_info(&client->dev, "DAC registered\n");
return 0;
exit_free_device:
iio_free_device(data->indio_dev);
exit_free_data:
kfree(data);
exit:
return err;
}
static int max517_remove(struct i2c_client *client)
{
struct max517_data *data = i2c_get_clientdata(client);
iio_free_device(data->indio_dev);
kfree(data);
return 0;
}
static const struct i2c_device_id max517_id[] = {
{ "max517", ID_MAX517 },
{ "max518", ID_MAX518 },
{ "max519", ID_MAX519 },
{ }
};
MODULE_DEVICE_TABLE(i2c, max517_id);
static struct i2c_driver max517_driver = {
.driver = {
.name = MAX517_DRV_NAME,
},
.probe = max517_probe,
.remove = max517_remove,
.suspend = max517_suspend,
.resume = max517_resume,
.id_table = max517_id,
};
static int __init max517_init(void)
{
return i2c_add_driver(&max517_driver);
}
static void __exit max517_exit(void)
{
i2c_del_driver(&max517_driver);
}
MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
MODULE_DESCRIPTION("MAX517/MAX518/MAX519 8-bit DAC");
MODULE_LICENSE("GPL");
module_init(max517_init);
module_exit(max517_exit);
/*
* MAX517 DAC driver
*
* Copyright 2011 Roland Stigge <stigge@antcom.de>
*
* Licensed under the GPL-2 or later.
*/
#ifndef IIO_DAC_MAX517_H_
#define IIO_DAC_MAX517_H_
/*
* TODO: struct max517_platform_data needs to go into include/linux/iio
*/
struct max517_platform_data {
u16 vref_mv[2];
};
#endif /* IIO_DAC_MAX517_H_ */
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